Child resistant features are widely sought for medicine containers, poison containers, and yet undiscovered applications. One type of child resistant feature is particularly popular for rigid bottles that are injection molded, as typified by U.S. Pat. No. 6,039,195 to Konefal et al. Konefal et al. disclose a container having an open upper end and external threads formed on a neck finish proximate the open upper end. Just below the threads, a deflectable release element is integrally formed on the container. The release element extends radially outwardly from the neck finish and defines an open space between the release element and the neck finish. The release element ordinarily engages lugs formed in a closure member of the container to resist removal of the closure member by a child, unless the release element is pressed radially inwardly and/or axially downwardly. The release element is easily manufactured using a regular injection molding process.
However, many types of useful articles are produced by single stage or multi-stage injection blow molding (IBM) process. Such articles could benefit from incorporation of the above-described child resistant features. IBM processes typically involve thermoplastic materials, such as high density polyethylene, polypropylene, polyethylene terephthalate, and the like. IBM apparatuses for molding such articles typically include a mold assembly having a core pin that inserts within a pair of mold halves that are split longitudinally, and that open and close together in a direction that is transverse with respect to a longitudinal axis of the core pin. Accordingly, the core pin and closed mold halves cooperate to define a mold cavity that corresponds in size and shape to the desired size and shape of the article being molded. A suitable thermoplastic resin is injected into the mold assembly through a gate at one end of the closed assembly to fill the mold cavity and thereby form the article.
Unfortunately, however, the release element of the above-described child resistant container is difficult to manufacture using current injection blow molding processes and apparatuses, because the release element can be damaged when the mold halves retract away from each other. In other words, the non-symmetrical and relatively complex geometry between the release element and the container renders it impossible to quickly extract the container from the molds without some type of damage to the release element.